* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: 'Quicksand', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    }

    :root {
      --primary: #1a73e8;
      --primary-light: #4d90fe;
      --bear-blue: #6ab7d8;
      --bear-dark: #4a7a9c;
      --bear-light: #e6f4ff;
      --dark: #202123;
      --darker: #18191c;
      --light: #f8f9fa;
      --gray: #343541;
      --light-gray: #40414f;
      --border: #565869;
      --accent: #ff8c00;
      --bg-light: #f5f5f5;
      --bg-dark: #1e1e1e;
      --surface-light: #ffffff;
      --surface-dark: #2a2a2a;
      --text-light: #333333;
      --text-dark: #dddddd;
      --msg-bg-dark: rgba(32, 33, 35, 0.6);
      --msg-bg-light: rgba(255, 255, 255, 0.7);
      --doc-header: #2e7d99;
      --doc-subheader: #4a7a9c;
      --doc-border: rgba(106, 183, 216, 0.3);
      --doc-bg: rgba(32, 42, 53, 0.5);
    }

    body {
      background: linear-gradient(135deg, #0a1929, #1a2a4a);
      color: var(--light);
      height: 100vh;
      overflow: hidden;
      display: flex;
    }

    body.light {
      background: linear-gradient(135deg, #d4e4f7, #c9d6ff);
    }

    /* Sidebar styling */
    .sidebar {
      width: 260px;
      background-color: rgba(25, 27, 33, 0.92);
      padding: 15px;
      display: flex;
      flex-direction: column;
      border-right: 1px solid var(--border);
      height: 100vh;
      overflow-y: auto;
      transition: all 0.3s;
      box-shadow: 0 0 20px rgba(0, 0, 0, 0.3);
      z-index: 10;
    }

    body.light .sidebar {
      background-color: rgba(255, 255, 255, 0.92);
      border-right: 1px solid rgba(0, 0, 0, 0.1);
    }

    .logo {
      display: flex;
      align-items: center;
      padding: 15px 10px;
      margin-bottom: 20px;
      border-bottom: 1px solid var(--border);
      position: relative;
    }

    .logo::after {
      content: "";
      position: absolute;
      bottom: -5px;
      left: 50%;
      transform: translateX(-50%);
      width: 40px;
      height: 5px;
      background: var(--bear-blue);
      border-radius: 5px;
    }

    body.light .logo {
      border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    }

    .logo-icon {
      font-size: 28px;
      color: var(--bear-blue);
      margin-right: 12px;
    }

    .logo-text {
      font-size: 22px;
      font-weight: 700;
      background: linear-gradient(90deg, var(--bear-blue), #a8d8ea);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      letter-spacing: 0.5px;
    }

    .new-chat-btn {
      background: linear-gradient(135deg, var(--bear-blue), #4a7a9c);
      color: white;
      border: none;
      padding: 12px 15px;
      border-radius: 12px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      transition: all 0.3s ease;
      position: relative;
      overflow: hidden;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    }

    .new-chat-btn::before {
      content: "";
      position: absolute;
      top: 0;
      left: -100%;
      width: 100%;
      height: 100%;
      background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
      transition: 0.5s;
    }

    .new-chat-btn:hover::before {
      left: 100%;
    }

    .new-chat-btn:hover {
      transform: translateY(-3px);
      box-shadow: 0 6px 12px rgba(74, 122, 156, 0.3);
    }

    .new-chat-btn i {
      margin-right: 8px;
    }

    .history {
      flex: 1;
      overflow-y: auto;
      padding: 10px;
    }

    .history-title {
      font-size: 14px;
      color: #9ca3af;
      padding: 10px 5px;
      margin-top: 10px;
      display: flex;
      align-items: center;
    }

    .history-title::before {
      content: "";
      flex: 1;
      height: 1px;
      background: var(--border);
      margin-right: 10px;
    }

    .history-title::after {
      content: "";
      flex: 1;
      height: 1px;
      background: var(--border);
      margin-left: 10px;
    }

    body.light .history-title {
      color: #666;
    }

    .history-empty {
      text-align: center;
      color: #9ca3af;
      padding: 30px 0;
      font-style: italic;
    }

    .conversation-item {
      padding: 10px;
      margin: 5px 0;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.3s;
      display: flex;
      align-items: center;
    }

    .conversation-item:hover {
      background-color: rgba(255, 255, 255, 0.08);
    }

    .conversation-item i {
      margin-right: 10px;
      color: var(--bear-blue);
    }

    body.light .conversation-item:hover {
      background-color: rgba(0, 0, 0, 0.05);
    }

    .sidebar-footer {
      padding: 15px 0;
      border-top: 1px solid var(--border);
      margin-top: auto;
    }

    body.light .sidebar-footer {
      border-top: 1px solid rgba(0, 0, 0, 0.1);
    }

    .user-info {
      display: flex;
      align-items: center;
      padding: 10px;
      border-radius: 8px;
      transition: background 0.3s;
      cursor: pointer;
    }

    .user-info:hover {
      background-color: rgba(255, 255, 255, 0.08);
    }

    body.light .user-info:hover {
      background-color: rgba(0, 0, 0, 0.05);
    }

    .user-avatar {
      width: 36px;
      height: 36px;
      border-radius: 50%;
      background: linear-gradient(135deg, var(--primary), var(--accent));
      display: flex;
      align-items: center;
      justify-content: center;
      margin-right: 12px;
      font-weight: 600;
      color: white;
    }

    .user-name {
      font-weight: 500;
      font-size: 15px;
    }

    /* Main chat area */
    .main {
      flex: 1;
      display: flex;
      flex-direction: column;
      height: 100vh;
      position: relative;
      overflow: hidden;
      background: linear-gradient(135deg, rgba(10, 25, 41, 0.9), rgba(26, 42, 74, 0.9));
    }

    body.light .main {
      background: linear-gradient(135deg, rgba(212, 228, 247, 0.9), rgba(201, 214, 255, 0.9));
    }

    .chat-header {
      padding: 20px;
      text-align: center;
      background-color: rgba(25, 27, 33, 0.95);
      backdrop-filter: blur(10px);
      position: relative;
      z-index: 2;
      box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    }

    body.light .chat-header {
      background-color: rgba(255, 255, 255, 0.95);
    }

    .chat-title {
      font-size: 24px;
      font-weight: 700;
      margin-bottom: 5px;
      color: var(--light);
      background: linear-gradient(90deg, #a8d8ea, var(--bear-blue));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      letter-spacing: 0.5px;
    }

    body.light .chat-title {
      color: var(--text-light);
    }

    .chat-subtitle {
      font-size: 14px;
      color: var(--bear-blue);
      font-style: italic;
    }

    body.light .chat-subtitle {
      color: #4a7a9c;
    }

    .chat-container {
      flex: 1;
      overflow-y: auto;
      padding: 30px 20px 100px;
      display: flex;
      flex-direction: column;
      position: relative;
      z-index: 1;
    }

    @media (min-width: 768px) {
      .chat-container {
        padding: 30px 15% 100px;
      }
    }

    /* Message Styles - Improved for readability */
    .message {
      padding: 15px 0;
      display: flex;
      animation: fadeIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
      opacity: 0;
      transform: translateY(15px);
    }

    @keyframes fadeIn {
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    .bot-msg {
      justify-content: flex-start;
    }

    .user-msg {
      justify-content: flex-end;
    }

    .avatar {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 12px;
      flex-shrink: 0;
      z-index: 2;
    }

    .bot-msg .avatar {
      background: linear-gradient(135deg, var(--bear-blue), var(--bear-dark));
      box-shadow: 0 3px 6px rgba(74, 122, 156, 0.3);
    }

    .user-msg .avatar {
      background: linear-gradient(135deg, var(--primary), var(--primary-light));
      box-shadow: 0 3px 6px rgba(26, 115, 232, 0.3);
    }

    .avatar i {
      font-size: 18px;
      color: white;
    }

    .message-content {
      max-width: 75%;
      padding: 15px 20px;
      border-radius: 18px;
      position: relative;
      background: var(--msg-bg-dark);
      backdrop-filter: blur(5px);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    }

    body.light .message-content {
      background: var(--msg-bg-light);
    }

    .bot-msg .message-content {
      border-top-left-radius: 5px;
      margin-right: auto;
      border-left: 3px solid var(--bear-blue);
    }

    .user-msg .message-content {
      border-top-right-radius: 5px;
      margin-left: auto;
      border-right: 3px solid var(--primary);
    }

    .message-content p {
      line-height: 1.6;
      font-size: 16px;
      color: var(--light);
    }

    body.light .message-content p {
      color: var(--text-light);
    }

    .bot-msg .message-content p {
      white-space: pre-wrap;
    }

    /* Input area */
    .input-container {
      position: relative;
      padding: 20px;
      background: rgba(32, 33, 35, 0.7);
      backdrop-filter: blur(10px);
      border-top: 1px solid var(--border);
      z-index: 2;
    }

    body.light .input-container {
      background: rgba(255, 255, 255, 0.7);
      border-top: 1px solid rgba(0, 0, 0, 0.1);
    }

    .input-box {
      position: relative;
      max-width: 800px;
      margin: 0 auto;
      display: flex;
      align-items: center;
      background: rgba(64, 65, 79, 0.5);
      border-radius: 24px;
      border: 1px solid var(--border);
      transition: all 0.3s ease;
    }

    body.light .input-box {
      background: rgba(255, 255, 255, 0.7);
      border: 1px solid rgba(0, 0, 0, 0.1);
    }

    .input-box:focus-within {
      border-color: var(--bear-blue);
      box-shadow: 0 0 0 3px rgba(106, 183, 216, 0.3);
    }

    .input-box input {
      flex: 1;
      background: transparent;
      border: none;
      color: var(--light);
      font-size: 1rem;
      padding: 16px 20px;
      outline: none;
      height: 60px;
    }

    body.light .input-box input {
      color: var(--text-light);
    }

    .input-box input::placeholder {
      color: #9ca3af;
    }

    body.light .input-box input::placeholder {
      color: #888;
    }

    .input-box button {
      width: 50px;
      height: 50px;
      margin-right: 8px;
      border: none;
      background: var(--bear-blue);
      color: white;
      font-weight: bold;
      border-radius: 50%;
      cursor: pointer;
      transition: all 0.3s;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .input-box button:hover {
      background: var(--bear-dark);
      transform: scale(1.05);
    }

    .bear-watermark {
      position: absolute;
      bottom: 40px;
      right: 40px;
      opacity: 0.04;
      z-index: 0;
      pointer-events: none;
      font-size: 200px;
      color: var(--bear-blue);
    }

    body.light .bear-watermark {
      opacity: 0.03;
    }

    .wise-quote {
      position: absolute;
      bottom: 150px;
      left: 50%;
      transform: translateX(-50%);
      width: 80%;
      max-width: 600px;
      text-align: center;
      font-style: italic;
      color: rgba(255, 255, 255, 0.15);
      font-size: 18px;
      z-index: 0;
    }

    body.light .wise-quote {
      color: rgba(0, 0, 0, 0.1);
    }

    /* Theme toggle button */
    .toggle-btn {
      position: absolute;
      top: 20px;
      right: 20px;
      background: rgba(32, 33, 35, 0.7);
      border: 1px solid var(--border);
      color: var(--accent);
      width: 40px;
      height: 40px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      z-index: 10;
      font-size: 18px;
      transition: all 0.3s;
    }

    .toggle-btn:hover {
      transform: rotate(15deg);
    }

    body.light .toggle-btn {
      background: rgba(255, 255, 255, 0.7);
      border: 1px solid rgba(0, 0, 0, 0.1);
    }

    /* Welcome Bear Animation */
    .welcome-overlay {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(10, 25, 41, 0.95);
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      z-index: 100;
      opacity: 1;
      transition: opacity 1s ease-out;
    }

    .welcome-bear {
      font-size: 120px;
      color: var(--bear-blue);
      margin-bottom: 30px;
      animation: bearAppear 2s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
      transform: translateY(100px) scale(0.5);
      opacity: 0;
    }

    @keyframes bearAppear {
      0% {
        transform: translateY(100px) scale(0.5);
        opacity: 0;
      }
      100% {
        transform: translateY(0) scale(1);
        opacity: 1;
      }
    }

    .welcome-message {
      font-size: 28px;
      text-align: center;
      max-width: 600px;
      padding: 0 20px;
      color: var(--light);
      animation: textAppear 1.5s 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
      opacity: 0;
      transform: translateY(30px);
    }

    @keyframes textAppear {
      0% {
        transform: translateY(30px);
        opacity: 0;
      }
      100% {
        transform: translateY(0);
        opacity: 1;
      }
    }

    .welcome-subtitle {
      font-size: 18px;
      margin-top: 20px;
      color: var(--bear-blue);
      font-style: italic;
      animation: textAppear 1.5s 1s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
      opacity: 0;
      transform: translateY(30px);
    }

    /* Responsive design */
    @media (max-width: 900px) {
      .sidebar {
        width: 70px;
      }
      .logo-text, .history-title, .history-text, .user-name {
        display: none;
      }
      .logo {
        justify-content: center;
        padding: 15px 0;
      }
      .new-chat-btn span {
        display: none;
      }
      .new-chat-btn i {
        margin-right: 0;
      }
      .chat-container {
        padding: 20px 10px 100px;
      }
      .welcome-message {
        font-size: 22px;
      }
      .welcome-subtitle {
        font-size: 16px;
      }
    }

    @media (max-width: 600px) {
      .sidebar {
        position: absolute;
        z-index: 100;
        transform: translateX(-100%);
        transition: transform 0.3s ease;
      }
      .sidebar.active {
        transform: translateX(0);
      }
      .menu-toggle {
        display: block;
        position: absolute;
        top: 20px;
        left: 20px;
        z-index: 99;
        background: rgba(32, 33, 35, 0.8);
        border: 1px solid var(--border);
        color: white;
        width: 40px;
        height: 40px;
        border-radius: 8px;
        display: flex;
        align-items: center;
        justify-content: center;
        cursor: pointer;
      }
      body.light .menu-toggle {
        background: rgba(255, 255, 255, 0.8);
        border: 1px solid rgba(0, 0, 0, 0.1);
        color: #333;
      }
      .message-content {
        max-width: 85%;
      }
      .welcome-bear {
        font-size: 80px;
      }
      .welcome-message {
        font-size: 20px;
      }
      .welcome-subtitle {
        font-size: 14px;
      }
    }

    .menu-toggle {
      display: none;
    }

    /* Loading animation */
    .typing-indicator {
      display: flex;
      align-items: center;
      padding: 10px 0;
    }

    .dot {
      width: 10px;
      height: 10px;
      background-color: var(--bear-blue);
      border-radius: 50%;
      margin: 0 4px;
      animation: bounce 1.4s infinite ease-in-out both;
    }

    .dot:nth-child(1) {
      animation-delay: -0.32s;
    }

    .dot:nth-child(2) {
      animation-delay: -0.16s;
    }

    @keyframes bounce {
      0%, 80%, 100% {
        transform: scale(0);
      }
      40% {
        transform: scale(1);
      }
    }
    
    /* Animated Bear Container */
    .animated-bear {
      position: absolute;
      bottom: 40px;
      right: 40px;
      width: 200px;
      height: 200px;
      z-index: 0;
      pointer-events: none;
      opacity: 0.1;
      transition: opacity 0.5s ease;
    }
    
    .thinking .animated-bear {
      opacity: 0.3;
      animation: thinking 2s infinite ease-in-out;
    }
    
    @keyframes thinking {
      0%, 100% { transform: translateY(0) rotate(0); }
      25% { transform: translateY(-5px) rotate(2deg); }
      50% { transform: translateY(0) rotate(0); }
      75% { transform: translateY(-5px) rotate(-2deg); }
    }
    
    .bear-body {
      position: absolute;
      width: 140px;
      height: 120px;
      background: var(--bear-blue);
      border-radius: 50% 50% 40% 40%;
      bottom: 40px;
      right: 30px;
    }
    
    .bear-head {
      position: absolute;
      width: 100px;
      height: 90px;
      background: var(--bear-blue);
      border-radius: 45% 45% 40% 40%;
      bottom: 140px;
      right: 50px;
    }
    
    .bear-ear {
      position: absolute;
      width: 40px;
      height: 40px;
      background: var(--bear-dark);
      border-radius: 50%;
      z-index: -1;
    }
    
    .ear-left {
      bottom: 165px;
      right: 75px;
    }
    
    .ear-right {
      bottom: 165px;
      right: 85px;
    }
    
    .bear-eye {
      position: absolute;
      width: 12px;
      height: 12px;
      background: #000;
      border-radius: 50%;
      bottom: 185px;
    }
    
    .eye-left {
      right: 75px;
    }
    
    .eye-right {
      right: 55px;
    }
    
    .bear-nose {
      position: absolute;
      width: 25px;
      height: 15px;
      background: var(--bear-dark);
      border-radius: 35%;
      bottom: 170px;
      right: 62px;
    }
    
    .thought-bubble {
      position: absolute;
      width: 80px;
      height: 60px;
      background: rgba(255, 255, 255, 0.2);
      border-radius: 50%;
      bottom: 220px;
      right: 140px;
      display: none;
      justify-content: center;
      align-items: center;
    }
    
    .thinking .thought-bubble {
      display: flex;
      animation: bubbleFloat 3s infinite ease-in-out;
    }
    
    @keyframes bubbleFloat {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-10px); }
    }
    
    .thought-dots {
      display: flex;
      gap: 5px;
    }
    
    .thought-dot {
      width: 8px;
      height: 8px;
      background: white;
      border-radius: 50%;
      animation: dotPulse 1.5s infinite ease-in-out;
    }
    
    .thought-dot:nth-child(1) { animation-delay: 0s; }
    .thought-dot:nth-child(2) { animation-delay: 0.3s; }
    .thought-dot:nth-child(3) { animation-delay: 0.6s; }
    
    @keyframes dotPulse {
      0%, 100% { transform: scale(1); opacity: 0.7; }
      50% { transform: scale(1.3); opacity: 1; }
    }
    
    .bear-arm {
      position: absolute;
      width: 50px;
      height: 20px;
      background: var(--bear-blue);
      border-radius: 10px;
      bottom: 110px;
      right: 15px;
      transform-origin: top right;
      animation: none;
    }
    
    .thinking .bear-arm {
      animation: armThink 2s infinite ease-in-out;
    }
    
    @keyframes armThink {
      0%, 100% { transform: rotate(0); }
      50% { transform: rotate(-20deg); }
    }
    
    /* Enhanced features */
    .message-timestamp {
      font-size: 11px;
      color: #9ca3af;
      margin-top: 5px;
      text-align: right;
    }
    
    .bot-msg .message-timestamp {
      text-align: left;
    }
    
    .message-actions {
      position: absolute;
      top: 5px;
      right: 10px;
      opacity: 0;
      transition: opacity 0.3s;
    }
    
    .message:hover .message-actions {
      opacity: 1;
    }
    
    .message-action {
      background: none;
      border: none;
      color: var(--bear-blue);
      cursor: pointer;
      font-size: 14px;
      margin-left: 5px;
    }
    
    .message-action:hover {
      color: var(--bear-dark);
    }
    
    .conversation-history {
      max-height: calc(100vh - 300px);
      overflow-y: auto;
    }
    
    .conversation-item {
      padding: 10px;
      margin: 5px 0;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.3s;
      display: flex;
      align-items: center;
    }
    
    .conversation-item.active {
      background-color: rgba(106, 183, 216, 0.2);
    }
    
    .conversation-item:hover {
      background-color: rgba(106, 183, 216, 0.15);
    }
    
    .conversation-title {
      flex: 1;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }
    
    .conversation-date {
      font-size: 12px;
      color: #9ca3af;
      margin-left: 5px;
    }
    
    .system-notification {
      position: fixed;
      bottom: 20px;
      left: 50%;
      transform: translateX(-50%);
      background: rgba(25, 27, 33, 0.9);
      color: white;
      padding: 10px 20px;
      border-radius: 8px;
      z-index: 100;
      opacity: 0;
      transition: opacity 0.3s;
      backdrop-filter: blur(10px);
    }
    
    .system-notification.show {
      opacity: 1;
    }
    
    /* Documented Text Styles */
    .documented-response {
      padding: 15px;
      border-radius: 12px;
      background: var(--doc-bg);
      border: 1px solid var(--doc-border);
      margin: 10px 0;
    }
    
    .doc-header {
      font-size: 1.4rem;
      font-weight: 700;
      color: var(--bear-blue);
      margin-bottom: 15px;
      padding-bottom: 8px;
      border-bottom: 2px solid var(--doc-border);
    }
    
    .doc-subheader {
      font-size: 1.2rem;
      font-weight: 600;
      color: var(--bear-light);
      margin: 15px 0 8px 0;
      padding-left: 8px;
      border-left: 3px solid var(--bear-blue);
    }
    
    body.light .doc-subheader {
      color: var(--bear-dark);
    }
    
    .doc-content {
      line-height: 1.7;
      margin-bottom: 15px;
    }
    
    .doc-list {
      padding-left: 25px;
      margin: 10px 0;
    }
    
    .doc-list li {
      margin-bottom: 8px;
      position: relative;
    }
    
    .doc-list li:before {
      content: "•";
      color: var(--bear-blue);
      position: absolute;
      left: -15px;
      font-size: 1.2rem;
    }
    
    .doc-footer {
      margin-top: 20px;
      padding-top: 15px;
      border-top: 1px solid var(--doc-border);
      font-style: italic;
      color: var(--bear-blue);
    }
    
    .doc-code {
      background: rgba(0, 0, 0, 0.2);
      padding: 12px;
      border-radius: 8px;
      font-family: monospace;
      margin: 10px 0;
      overflow-x: auto;
      border-left: 3px solid var(--bear-blue);
    }
    
    .doc-table {
      width: 100%;
      border-collapse: collapse;
      margin: 15px 0;
    }
    
    .doc-table th {
      background: rgba(74, 122, 156, 0.3);
      padding: 10px;
      text-align: left;
      font-weight: 600;
      color: var(--bear-light);
    }
    
    .doc-table td {
      padding: 10px;
      border-bottom: 1px solid var(--doc-border);
    }
    
    .doc-table tr:last-child td {
      border-bottom: none;
    }
    
    .doc-highlight {
      background: rgba(106, 183, 216, 0.2);
      padding: 3px 6px;
      border-radius: 4px;
      font-weight: 500;
    }
    
    .doc-tip {
      background: rgba(74, 122, 156, 0.15);
      border-left: 4px solid var(--bear-blue);
      padding: 12px 15px;
      margin: 15px 0;
      border-radius: 0 8px 8px 0;
    }
    
    .doc-tip-header {
      display: flex;
      align-items: center;
      margin-bottom: 5px;
      font-weight: 600;
      color: var(--bear-blue);
    }
    
    .doc-tip-header i {
      margin-right: 8px;
    }